I dont think it proves Lennie wrong because George didn't kill lennie just because of what he had done to the dog and to Curleys wife ,Im pretty sure everyone was glad that she wasn't gonna be around anymore .George shot Lennie because he didn't wanna see him suffer because of what he had done ,they could have sent him to an insane asylum or they would have sent him to prison. So George that it was would easier to kill him instead of having him suffer somewhere else .So its kinda like George was doing Lennie a favor but then again if you think about it ,it was pretty hard for George to shoot him because they have never left each other like they would travel everywhere together and they were almost inseparable .But right after George shot him
